This invention is directed to a composition of matter. In general the composition is a polyamide copolymer. One of the two components of the copolymer is a polyetheramide e.g., a poly(dioxa-alkylamide), a poly(dioxa-arylamide), or a poly(oxa-amide). The other component is a random copolymer which can result from, but is not limited to, the polycondensation of a precursor of the aforementioned polyetheramide, and a precursor of an ether-free polyamide. In particular the invention is directed to a block copolymer consisting of the two aforementioned components. The block copolymer has utility, as, for example, a fiber. A preferred composition is one wherein the random copolymer is formed, in part from a precursor of a polyamide which is considered to be difficult to form a block copolymer because its transamidation rate at a temperature above its melting point is relatively rapid; an example is nylon 6,6. A rapid transamidation rate can be a disadvantage in two processing steps, one, when the block copolymer is formed and, two, when the block copolymer is melt spun into a fiber.
U.S. Pat. No. 4,130,602 discloses a block copolymer of a poly(dioxa-alkylamide) and a polyamide. U.S. Application Ser. No. 773,740, filed Mar. 2, 1977 discloses a block copolymer of a poly(dioxa-arylamide) and a polyamide. U.S. Pat. No. 4,136,133 discloses a block copolymer of poly(oxa-amide) and a polyamide. U.S. Pat. No. 4,113,794 discloses a copolymer of blocks of a random poly(dioxa-amide) and a polyamide. U.S. Pat. No. 4,045,511 discloses a process for melt blending particles of a melt spinnable polyamide and a salt of an ether diamine and a dicarboxylic acid. U.S. Pat. No. 4,044,071 discloses a process for melt blending a molten-spinnable polyamide and a salt of an ether diamine and a dicarboxylic acid.
In the preceding prior art the polyamide portion of the copolymer is essentially a polyamide in that, for example, it contains no ether linkages, i.e., dioxa or oxa linkages. In contrast, the polyamide portion of the present composition does contain ether linkages.
U.S. Pat. No. 3,509,106 discloses the preparation of a random copolymer polycondensate of an adipic acid salt of ethylene-bis-(3-aminopropyl)ether and hexamethylene diammonium adipate (6,6 salt), the mole ratio of the former to the latter being for example in the range from 9:1 to 1:9. A function of the ether type additive is to enhance the moisture absorption of the resulting polycondensate compared to nylon 6,6 by itself. But this prior art does not disclose or suggest using the random polycondensate to form a block copolymer with a polyetheramide.